1. Field of the Invention
The present invention relates to a photographic camera and more particularly, to a photographic camera capable of writing photographic information onto a film as magnetic data and reading the magnetic data therefrom.
2. Description of the Related Art
Japanese Patent Laid-Open Publication No. 60-17447 and U.S. Pat. No. 4,482,924 disclose a film having a magnetic surface formed out of magnetic material thereon so that photographic data can be written onto the film and read therefrom. A camera dealing with the photographic data by using this kind of film requires a magnetic head that is in dose contact the magnetic surface of the film, for example, a pad for pressing the film against the magnetic head is also required.
According to a conventional method for loading a film into the camera body, the leading end portion of a film is taken out for a fixed length from a patrone so that the perforations of the film positioned in the leading end portion thereof will engage the sprockets positioned on the spool side and the lid will be closed. Consequently, a user may touch the magnetic surface, which causes errors. In order to solve this problem which occurs in using this kind of film, it is preferable to provide a camera with an automatic loading mechanism which sends the film from a cartridge sending the leading end portion of the film by driving a camera, winds the film around the spool and automatically advances the film to an exposure position, only by setting the cartridge in which film is completely accommodated in the predetermined position and closing the lid.
In the camera using a film having a magnetic surface thereon, since a magnetic head is provided as above described, the leading end portion of the film may be caught by the magnetic head or the pad in sending the film from the cartridge and winding it around the spool and as a result, the automatic loading mechanism does not function normally. This is not preferable for a film and of course must be prevented. When such a loading mistake occurs, a troublesome operation such as taking out and reloading the film is needed.
Meanwhile, in order to protect certainly at least exposed frames, a pre-winding system is conventionally adopted. According to this system, in loading a cartridge, a film is taken out from a cartridge and wound around the spool before a photographing operation is performed and the film is rewound into the cartridge frame by frame after each frame is exposed. In the case that a camera and a cartridge are constructed so that the film can be re-loaded, using the pre-winding system is useful.